FR2735089A1 - ELECTRONICALLY CONTROLLED SPEED CHANGE DEVICE FOR BICYCLES - Google Patents

Abstract

An electronically controlled gear shifting device for bicycles has an automatic mode of operation in which, at the request of the rider to increase or decrease the gear ratio, the system automatically ensures the selection of gear by itself. the chainring-pinion pair which is the most suitable for respectively providing a progressive increase or a progressive decrease in the distance traveled by the bicycle on each pedal revolution.

Description

I The present invention relates to a device for changing

  speed for bicycles, of the type comprising: a front derailleur and a rear derailleur intended to control the selective engagement of a bicycle chain with several chainwheels associated with the pedal of the bicycle and several sprockets associated with the hub of the rear bicycle wheel, a first and a second electric motor respectively associated with the front derailleur and with the rear derailleur, for the control thereof, means intended to detect the operational position of the front derailleur and of the rear derailleur, activation means controlled manually for activating the first and second electric motors, and an electronic control unit for controlling the speed change device, which is connected to said first and second electric motors, to said detection means and to said

means of activation.

  A device of the type indicated above formed the subject of Italian patent application No. TO93A000503 filed by the present applicant on July 8, 1993 and submitted to public inspection on January 8, 1995, as well as the corresponding French patent application No. 2,708,559, and the corresponding German patent application n 44 22 845. An improvement of this device also constituted the subject of the Italian patent application n TO94A000116 of February 24, 1994, filed by the present applicant and still secret on the date priority of this request. The object of the present invention is to further improve the device constituting the subject of the patent applications mentioned above so as to allow extremely easy and rapid use by the cyclist. This need is felt particularly (although not exclusively) in the case of racing bicycles, since the rider must keep his attention as much as possible on the race even when he makes a gear change, in particular without losing precious seconds to decide which chainring and pinion combination should be

chosen.

  In order to achieve this object, the invention provides a speed change device for a bicycle of the type indicated at the start, characterized in that said activation means comprise first and second actuation elements controlled manually, in order to cause respectively an increase or a decrease in speed on each actuation, and in that said electronic control unit is programmed so as to automatically select, each time one of the two actuating elements is activated, the chainring and the pinion on which must be engaged the chain to ensure a progressive increase or decrease in the distance traveled by the bicycle at each pedal turn, the electronic control unit providing as a consequence of the actuation of one or both electric motors to obtain the required condition of engagement of the chain on the chosen chainring and the chosen sprocket, starting from the co Edition indicated by said detection means, and finally providing for stopping the electric motor which has been activated, or both electric motors, if they have been activated both, when said detection means

  detect that said required condition has been reached.

  As is clearly apparent, the concept which is the basis of the present invention is therefore a particular strategy which is followed by the electronic control unit in order to select the chainring-pinion pair at each gear change. If it is assumed, for example, that the cyclist wishes to increase the speed, he actuates the actuating element once or more

  controls the shift to higher speeds.

  Each actuation of the actuating element causes a speed change. At each gear change, the electronic control unit selects a chainring pair so that there is a gradual increase in the distance traveled by the bicycle with each turn of the pedal.

  with the change from one speed to the next.

  Conversely, in the case where the cyclist actuates one or more times the actuating element which controls the reduction in speed, the plate-pinion pairs are chosen each time so as to ensure a progressive reduction in the distance traveled.

each pedal turn.

  Naturally, the system can be provided with selection means intended to allow the user to control the operation according to the semi-automatic mode which has been described above or else according to a completely manual mode, in which the user controls separately. the front derailleur

  and the rear derailleur as desired.

  The concept which is the basis of the present invention therefore resides in the choice of a progressive or regressive criterion relating to the distance traveled at each pedal turn when selecting the chainring pair at each

gear switch.

  Other characteristics and advantages of the present invention will appear on reading the

  following description with reference to the drawings

  attached, given simply by way of nonlimiting example, in which: FIG. 1 schematically shows a perspective view of a bicycle provided with a device according to the present invention, FIG. 2 is a block diagram of the device according to invention, Figure 3 shows a flowchart which relates to an operating mode of the device according to the invention, and Figure 4 shows a table corresponding to a possible operating criterion of the device

according to the invention.

  Referring to Figure 1, the reference 1 generally designates a racing bicycle consisting essentially of a frame 2 typically formed by tubular elements defining a support structure 3 for a wheel rear 4 and a fork 5 for a front wheel 6 with which is associated a handlebar 70 which also has a

tubular structure.

  The frame 2 at its lower part supports a crankset 7, of conventional type, in order to actuate the rear wheel 4 by means of a speed change device according to the invention,

  generally designated by reference 8.

  The speed change device 8 essentially consists of a rear speed change 9 and a front speed change 10 comprising, in a generally known manner, several pinions 11 (eight in the example illustrated) having different diameters and coaxial with the axis A of the rear wheel 4, and several plates 12 (two in the example illustrated) having different diameters and

coaxial with the axis B of the crankset 7.

  The pinions 11 and the chainrings 12 can be selectively engaged by an endless transmission chain 13, in order to obtain the different gear ratios available by means of the gear change device 8, by respectively moving a rear derailleur 14 of the shift

  rear gear 9 and a front derailleur 15.

  According to the solution proposed in the previous patent applications of the same applicant which were cited above, the front derailleur 15 and the rear derailleur 14 are both provided with an electric motor with respective reduction gear (which are shown simply schematically on the Figure 2 by the references 14a and 15a) which are used to cause the displacement of the derailleur so as to cause the chain to derail on the different sprockets

  or the different trays respectively.

  The construction details of said electric reducer motors and their mounting on the derailleur are not illustrated here because they are represented in said earlier patent applications of the applicant. The same applies to an encoding device (designated by the reference 14b and b in FIG. 2) which is associated with each geared motor and acts as a detector of the position of the reduction unit of the motor. and therefore the associated derailleur. Again in accordance with what has been shown in the previous patent applications of the present applicant, the power supply to the geared motors 14a, 15a is provided by a battery 30 (Figure 1) housed advantageously in one of the tubes of the frame 2 or, as a variant, in one of the arms of the handlebar 70, or in the housing of a microprocessor control unit 40 (FIG. 1) which is fixed for example to the frame of the bicycle in the crankset area and ensures the system control

  manner which will be shown in detail later.

  The two rear and front derailleurs 14 and 15 are controlled by said microprocessor control unit 40 on the basis of the signals delivered by two manually operated actuation levers 43, 44 associated with a brake lever 41 (FIG. 1). The microprocessor unit 40 (which can also be housed in the brake lever unit) is also connected, as shown in FIG. 2, to the two encoders 14b, 15b which detect the position of the respective derailleurs 14, 15 , in order to stop the respective actuating electric motor when the desired transmission ratio is reached, this ratio being determined by manual actuation levers 43, 44 which respectively serve to move towards

  higher and lower speeds.

  The connections of said components are provided by wires (not shown in FIG. 1) advantageously housed inside the tubes of frame 2. Again according to another characteristic known thanks to the previous patent applications of the applicant, the battery 30 can be of the rechargeable type, and the rear derailleur can incorporate a dynamoelectric unit, of a type known per se, mounted in one of the wheels 14c of the conventional guide element associated with the rear derailleur, in order

  ensure the battery is recharged.

  In the preferred embodiment of the invention which is described here, the electronic control unit 40 is programmed to allow two different modes of operation, which can be chosen by the cyclist by actuating a selector lever or button. According to a first manual operating mode, the cyclist controls separately

  the front derailleur 15 and the rear derailleur 14.

  For each of the two derailleurs, it therefore actuates a separate control device which causes the shift to higher or lower gear ratios. The details of this control device are not illustrated here, the fact that they can be made in any known manner and the fact that they do not fall, taken

  in isolation, within the scope of the present invention.

  According to the most important aspect of the invention, the electronic control unit 40 allows

  also a semi-automatic operating mode.

  In this case, the cyclist must again actuate two separate control devices, for example the levers 43, 44. However, each of these control devices simultaneously controls the front derailleur and the rear derailleur and serves to cause the shift to gears higher or lower respectively. It is of course the system which decides, without any intervention from the cyclist, which is each time the chainring-pinion pair which must be selected. According to the invention, the criterion adopted in order to select the chainring-pinion pair is that which ensures that, when switching to higher speeds or to lower speeds, a gradual increase or decrease in the distance covered by the bicycle with each pedal turn occurs. In other words, when the cyclist wishes to change speed, he must simply actuate one or more times one of the two actuating levers 43, 44 (depending on whether he wishes to go towards higher or lower speeds ) without having to worry about deciding each time which is the chainring-pinion combination that best suits his needs. Each time one of the buttons 43, 44 is actuated, the system itself automatically controls the rear derailleur and if necessary also the front derailleur in order to select the chainring-pinion pair which is the

more appropriate.

  The operating principle can be more easily understood by referring to FIG. 4, which shows a table relating to a possible example of use of the invention. This table relates to the case where eight pinions are provided (numbered on the lower line of the table from 1 to 8) having respectively 12, 13, 14, 15, 16, 17, 19 and 21 teeth, and o two plates are provided , designated by A and B in the right column of the table, and having 39 and 52 teeth respectively. The table shows, for each chainring-pinion combination, the distance in meters

  covered by the bicycle at each pedal turn.

  The electronic control unit 40 is programmed to automatically provide, at each actuation by the cyclist, the most appropriate selection of pinion plate. In the illustrated case, the combination corresponding to the lower speed is that of chainring A with pinion 8 (distance covered at each pedal revolution: 3.91 m). If it is assumed to be in this condition, if the cyclist actuates lever 43 one or more times in order to cause one or more passages to higher speeds, the system automatically plans to switch to the other combinations illustrated, following the path represented by the arrows in figure 4. Consequently, we move on to combinations A-7, A-6, A-5, A-4, A-3, B-6 (for this passage, the system consequently also causes the front derailleur to move), BS, B-4, B-3, B-2 and B-1. As shown, for said passages, the distance covered at each turn of the pedal subsequently increases to 4.32 m, 4.83 m, 5.13 m, 5.47 m, 5.86 m, 6.44 m, 6.84 m, 7.30 m, 7.82 m, 8.42 m, 9.12 m. As is therefore clear from this, on each actuation of an increase in speed applied by the cyclist, there is a progressive increase in the distance covered at each turn of the pedal. Naturally, if the cyclist actuates lever 44 one or more times in order to cause a reduction in speed, the process is exactly the opposite. Finally, as shown in the table, the values of the distances corresponding to the combinations A-1, A-2, B-7, B-8 have been deleted, since they are not

never chosen by the system.

  Naturally, sprockets and chainrings with a different number of teeth than those shown in

  As an example in Figure 4 can be used.

  For example, in a case tried in practice by the applicant, five different tables have been provided and correspond to five different groups of pinions and chainrings. The electronic control unit 40 is programmed to operate according to any one of these tables, and the cyclist has the possibility of teaching the system which table should be applied, as a function of the pinions and the plates which have been

mounted on the bicycle.

  As already indicated, if the cyclist nevertheless chooses the manual operating mode, he can operate the front derailleur and the rear derailleur directly and separately, thereby obtaining any desired condition. According to a characteristic constituting a subject of requests for

  Applicant's previous patents which have been cited above

  above, the system can in this case operate in order to command a small correction movement of the front derailleur when only the rear derailleur is actuated in such a way that the chain is moved to a position more inclined relative to the

  vertical longitudinal plane of the bicycle.

  FIG. 3 shows a flowchart corresponding to the logic operations which are carried out by the electronic control unit 40 following an actuation by the cyclist. As shown in this figure, the system first asks whether the automatic operating mode is required or not. If automatic operation is not required, the system operates in the conventional mode which has been mentioned above. If, however, automatic operation is enabled, the system asks whether an increase in speed is required or not. If an increase in speed is required, the system asks if the position of the rear derailleur 14 is at the maximum limit for the chainring which is actually engaged by the chain. For example, in the case of the table in FIG. 4, the system asks if, with the chainring A engaged, the pinion engaged is the pinion 3. If the system is in this condition, it calculates the position of the rear derailleur for the next chainring (in the example illustrated, the next chainring is the chain B and the next gear is therefore the gear 6). At this point, the system drives the rear derailleur to bring the chain to derail from the sprocket 3 to the sprocket 6. The system then drives the front derailleur to bring the chain to derail from chainring A to chainring B. If the system is however not at the maximum limit which was indicated above (pair A-3), the system simply drives the rear derailleur in order to move the chain to the next sprocket (always following the path represented by the arrows in Figure 4). Going back to the beginning of the flowchart, if there is no request for speed increase, the system asks if there is a request for speed reduction. In the affirmative case, the system asks if the rear derailleur is at the maximum limit for the chainring which is actually engaged by the chain (in other words, the system asks for example if, with chainring B engaged, the sprocket engaged is the pinion 6). In the negative case, the system simply drives the rear derailleur so as to position the chain on the next sprocket, again according to the

  path shown in the table of figure 4.

  However, in the affirmative case, the system calculates the position of the rear derailleur for the previous chainring and then positions the rear derailleur consecutively and then the front derailleur in order to obtain the appropriate pair (in the case of FIG. 4, the passage from pair B-6 to pair A-3

must be done).

  As already indicated, the electronic control system can be adjusted in the event of a replacement of the rear wheel, by setting the zero position for the position detection device of your choice at any of the two sprockets arranged at the ends of the sprocket unit. Of course, if this procedure were only possible for one of the two end sprockets, it would be necessary in certain situations to move the chain over all the sprockets in order to reach the position in which it is possible to determine the zero position. , so that at the end of this operation, a gear ratio very different from the previous one would be provided,

  which would cause disruption to the cyclist.

  The system can preferably be connected to an external device for diagnosis and / or a device for recharging the power supply battery. According to another characteristic, the electronic control system can carry out a diagnostic of

  battery status, and display it.

  Finally, according to another possible characteristic of the invention, the system comprises a digital display intended to indicate, inter alia, the positions of the front derailleur and of the rear derailleur; in addition, other parameters relating to the operation and performance of the bicycle

can be displayed.

  Naturally, although the principles of the invention remain the same, the construction details and the embodiments may vary widely from what has been described and illustrated by way of non-limiting example, without departing from it.

  of the scope of the present invention.

Claims (6)

  1. Gear change device for bicycles, comprising: a front derailleur (15) and a rear derailleur (14) intended to control the selective engagement of a bicycle chain (13) with several chainrings (12) associated with the crankset bicycle (7) and several pinions (11) associated with the hub of the rear bicycle wheel (4), a first and a second electric motor (15a, 14a) associated respectively with the front derailleur (15) and with the rear derailleur (14), for the control thereof, means (15b, 14b) intended to detect the operational position of the front derailleur (15) and the rear derailleur (14), activation means controlled manually (43, 44 ) intended to activate the first and second electric motors (14a, 15a), and an electronic control unit for the speed change device, which is connected to said first and second electric motors (14a, a), to said means of detection (1 4b, 15b) and said activation means (43, 44), characterized in that said activation means (43, 44) comprise first and second actuation elements controlled manually, in order to respectively control an increase or a reduction in the speed ratio on each actuation, and in that said electronic control unit (40) is programmed so as to carry out an automatic selection, each time one of the two actuating elements (43, 44) is activated, the plate (12) and the pinion (11) on which the chain (13) must be engaged in order to ensure a progressive increase or decrease in the distance traveled by the bicycle at each pedal turn, said unit of electronic control providing as a consequence of the actuation of one or both of the electric motors (14a, 15a) to obtain the desired engagement condition of the chain (13) on the plate (12) chosen and the pinion ( 11) chosen, in par both of the condition indicated by said detection means (14b, 15b), and finally providing for stopping the electric motor which has been activated, or else the two electric motors (14a, 15a), if they have both been activated , when said detection means (14b, b) detect that said desired condition has been reached. 2. A speed change device according to claim 1, characterized in that said electronic control unit (40) is connected to means intended for selecting the operating mode in order to choose between an automatic operating mode comprising said automatic selection, and a manual operating mode, in which it is possible to drive the derailleurs separately and manually rear and front (14, 15).   3. Gear change device according to claim 1, characterized in that the electronic control unit (40) is programmed to determine the zero position for the position detection device (14b, 15b), following d '' a replacement of the rear bicycle wheel, referring to any one of the two end gears of the pinion unit.   4. Speed change device according to claim 1, characterized in that said electronic control unit (40) is provided with means for connection to an external diagnostic device and / or for recharging the supply battery.   electric provided on the bicycle.   5. A speed change device according to claim 1, characterized in that the electronic control unit (40) is programmed in order to carry out diagnostics on the state of charge of a power supply battery provided on the bicycle and in order to deliver the corresponding information. 6. Gear change device according to claim 1, characterized in that it comprises a digital display connected to said electronic control unit (40) in order to display the positions of the   rear derailleur (14) and front derailleur (15).